Sold as either a Chevrolet Tahoe Hybrid or a GMC Yukon Hybrid, it's a full-size sport-utility with as many as eight seats and the capability to tow a boat that also delivers a fuel-economy gain and can even run on pure electricity.

The hybrid (which uses a 6.0-liter V-8 for better low-end torque) ought to get 19 to 20 mpg in the city and 21 or 22 mpg on the highway.

The target customer? "It's clearly going to be the customer who needs an SUV's five-, six-, seven-, eight-passenger capability. They tow their boats. They go camping. They really have a need for this SUV," says Micky Bly, GM's director of hybrid powertrain integration. "But they also want to make sure they're ecology-conscious, that it's important to get the best fuel economy."